The avatar feature in Grafana 3.0.1 through 7.0.1 has an SSRF Incorrect Access Control issue. This vulnerability allows any unauthenticated user/client to make Grafana send HTTP requests to any URL and return its result to the user/client. This can be used to gain information about the network that Grafana is running on. Furthermore, passing invalid URL objects could be used for DOS'ing Grafana via SegFault.
An information-disclosure flaw was found in Grafana through 6.7.3. The database directory /var/lib/grafana and database file /var/lib/grafana/grafana.db are world readable. This can result in exposure of sensitive information (e.g., cleartext or encrypted datasource passwords).
An issue was discovered in Grafana 5.4.0. Passwords for data sources used by Grafana (e.g., MySQL) are not encrypted. An admin user can reveal passwords for any data source by pressing the "Save and test" button within a data source's settings menu. When watching the transaction with Burp Proxy, the password for the data source is revealed and sent to the server. From a browser, a prompt to save the credentials is generated, and the password can be revealed by simply checking the "Show password" box.
In Grafana 2.x through 6.x before 6.3.4, parts of the HTTP API allow unauthenticated use. This makes it possible to run a denial of service attack against the server running Grafana.